Methods for forming group III-arsenide-nitride semiconductor materials

Abstract

Methods are disclosed for forming Group III-arsenide-nitride semiconductor materials. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

What is claimed is:  
     
       1. A method of incorporating larger concentrations of N relative to As at group V lattice sites in a III-V compound semiconductor crystal without experiencing defects due to lattice mismatch comprising the steps of: 
       providing a crystalline substrate;  
       epitaxially depositing on the substrate at least one set of a plurality of alternating groups of one or more layers comprising a first group having Group V atoms of all or a majority of nitrogen atoms at Group V lattice sites with at least one Group III element at Group III lattice sites and a second group having Group V atoms of all or a majority of arsenic atoms at Group V lattice sites with at least one Group III element at Group III lattice sites; and  
       depositing the layers in the first and second groups as monolayers so that the formation of defects due to lattice mismatch is avoided.  
     
     
       2. The method of  claim 1  wherein at least one of said layers has a crystal lattice that is maintained in strained relation with an adjoining layer. 
     
     
       3. The method of  claim 1  wherein some of the layers are comprised of binary semiconductor compounds. 
     
     
       4. A method of incorporating significant concentrations of at least N and As at group V lattice sites in a III-V compound semiconductor crystal comprising: 
       providing a crystalline substrate;  
       depositing at least one layer of a III-V semiconductor compound on the substrate having at least one element from Group III elements of Al, B, Ga and In disposed at group III lattice sites and having at least one element from Group V elements of As, N, P and Sb disposed at group V lattice sites;  
       the improvement comprising the step of  
       depositing said Group III element and said Group V element as separate and alternate monolayers of at least one Group III element absent of a Group V element and at least one Group V element absent of a Group III element sequentially on a [111] crystalline substrate to form the III-V compound semiconductor layer so that desorption of the Group III element is averted during deposition.  
     
     
       5. The method of  claim 1  further comprising the step of annealing the as-grown layers causing, at least in part, interlayer diffusion. 
     
     
       6. The method of  claim 1  comprising the step of depositing the layers at a temperature below 600° C. 
     
     
       7. The method of  claim 1  comprising the further step of providing nitrogen from molecules including hydrazine. 
     
     
       8. The method of  claim 1  comprising the further step of providing nitrogen from organometallic molecules containing N atoms. 
     
     
       9. The method of  claim 1  comprising the further step of providing nitrogen from dissociated NH 3  which has been cracked in an electron cyclotron resonator. 
     
     
       10. The method of  claim 1  comprising the further step of providing nitrogen from NH 3  which has been dissociated in a reaction catalyzed by AsH 3  and PH 3 . 
     
     
       11. The method of  claim 1  wherein the step of depositing of the layers includes LP-MOCVD. 
     
     
       12. The method of  claim 1  wherein the step of depositing of the layers includes MBE. 
     
     
       13. The method of  claim 1  comprising the further step of adding dopants during the deposition of at least some of the layers either of the first or second group or both groups. 
     
     
       14. The method of  claim 1  wherein the one other Group V atoms are arsenic. 
     
     
       15. The method of  claim 1  wherein the Group III elements are selected from the group consisting of one or more of B, Al Ga and In. 
     
     
       16. The method of  claim 1  comprising the further step of arranging the number of layers in the groups of the set such that the overall ratio of nitrogen atoms to the one other Group V atoms providing substantial lattice match with the crystalline substrate. 
     
     
       17. The method of  claim 15  wherein the first group of the layer or layers comprise GaN, GaAsN or InAsN and the second group of the layer or layers comprise GaAs, AlGaAs or InGaAs. 
     
     
       18. The method of  claim 1  wherein, in the second group, arsenic is the majority component in the Group V sites with above about 5% nitrogen at the Group V sites. 
     
     
       19. The method of  claim 1  wherein, in the first group, nitrogen is the majority component in the Group V sites with up to about 20% arsenic at the Group V sites. 
     
     
       20. The method of  claim 1  wherein at least one layer in the series of layers is a monolayer. 
     
     
       21. The method of  claim 1  wherein the substrate is selected from the group consisting of GaP, Si, GaAs, Ge, SiC, ZnSe, ZnO and diamond. 
     
     
       22. A method of incorporating significant concentrations of at least N and As at group V lattice sites in a III-V compound semiconductor crystal comprising: 
       providing a crystalline substrate;  
       depositing at least one layer of a III-V semiconductor compound on the substrate having a first group of at least one element from Group III elements of Al, B, Ga and In disposed at group III lattice sites and having a second group of at least one element from Group V elements of As, N, P and Sb disposed at group V lattice sites;  
       the improvement comprising the steps of  
       depositing semiconductor monolayers of first and second groups with the first group having N atoms at a majority of such atoms at Group V lattice sites with at least one Group III element at the group III lattice sites, and with the second group having As atoms at a majority of such atoms at Group V lattice sites with at least one Group III element at the Group III lattice sites; and  
       depositing said first and second groups as alternate monolayers of the Group III element absent of a Group V element and the Group V element absent of a Group III element so that desorption of Group III elements is averted during deposition of the layer.